Colloquium

Upcoming Colloquium

Bicrystals and Bowties: Photothermoelectric and Plasmonic effects of gold nanostructures
Dr. Charlotte Evans, Sandia National Laboratory

September 29, 2025
11:00am in HSCI-102

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The interaction of light with gold dramatically changes when the size of the gold devices is reduced to the nanoscale. The free electron gas in the metal can collectively oscillate with the electric field of the incident laser in an excitation called plasmons which can result in dramatic enhancements of the local electric field. Electronic transport and open circuit voltage (photothermoelectric) measurements can be powerful tools to characterize a gold nanoscale device heated by an incident laser. Measurements of the photothermoelectric voltage signal of single- and bi-crystalline gold wires provide evidence that these measurements have sensitivity to intrinsic variations in nanoscale devices that are otherwise difficult to detect using traditional electronic transport and imaging techniques. In nanoscale molecular junctions, Raman measurements can be combined with electronic transport measurements to detect the energy exchanges between the vibrational and electronic energy states in the molecule. However, the plasmonic resonances result in high local heating making these energy exchanges difficult to detect. We will discuss how photothermoelectric and electronic transport methods are powerful tools to not only characterize nanoscale devices but also to probe the plasmonic properties of the devices.

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